Method and device for identifying the operating condition of a turbine

ABSTRACT

The invention relates to a method for identifying the operating condition of a turbine during operation. According to said method, a hot waste gas flows through a waste gas housing and the temperature of the waste gas in said housing is detected using temporal resolution. The aim of the invention is to provide a method for identifying the operating condition of a turbine during operation, which identifies and displays systematic errors. To achieve this, the numerous measured temperature values for the waste gas are respectively detected using local resolution with reference to the origin of an imaginary Cartesian co-ordinate system. The focal point of the temperature distribution is then determined, a vector between the origin of the Cartesian co-ordinate system and the focal point of the temperature distribution being used as an indicator for the operating condition of the turbines.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage of International ApplicationNo. PCT/EP2004/008290, filed Jul. 23, 2004 and claims the benefitthereof. The International Application claims the benefits of EuropeanPatent application No. 03019868.3 filed Sep. 1, 2003, all of theapplications are incorporated by reference herein in their entirety.

FIELD OF THE INVENTION

A method for identifying an operating state during operation of aturbine, and a device for identifying an operating state duringoperation of a turbine.

The invention relates to a method for identifying an operating stateduring operation of a turbine in accordance with the claims, and to adevice for carrying out the method in accordance with the claims.

BACKGROUND OF THE INVENTION

It is known for the purpose of identifying an operating state of aturbine to detect and evaluate the temperatures prevailing in theexhaust gas continuously. Temperature measuring devices that detect thetemperatures of the exhaust gas are arranged distributed for thispurpose coaxially and uniformly on the inner wall of the exhaust gashousing. Extreme value comparisons are carried out in order to evaluatethe measured exhaust gas temperatures. The maximum and minimum occurringtemperatures are detected for each measuring point during trialoperation, and a temperature interval is thereby determined. Adisturbance is determined when the temperature measuring element detectsa temperature that lies outside its previously measured temperatureinterval.

It is also known to determine the difference from the time-averagedtemperature value of a temperature measuring device and theinstantaneous temperature, in order to determine the operating state.

These evaluations have the disadvantage that small systematic variationsin the exit temperatures that lie below the prescribed limits remainunconsidered.

It is known, furthermore, from US2002/183916 A1 to calculate the angleof rotation of the exit temperature field.

The determined angle of rotation is used to normalize the exittemperature field in order to enable temperature measuring points to beused to deduce dedicated Can combustion chambers.

Moreover, EP 1 118 920 A1 discloses vibration monitoring of rotatingcomponents. One or more vibration sensors arranged offset from oneanother are provided for this purpose. The recorded amplitudes and phaseangles of the vibrations or of the temporary displacements caused by thevibrations are detected with the aid of these sensors and decomposedinto two mutually perpendicular components that are subsequentlyconverted with the formation in each case of a sliding arithmetic meanvalue to form a resulting variable with amplitude and phase angle, whichvariable is then evaluated for the purpose of analyzing state.

Again, a display for a turbine exit temperature field is known from JP02-064232.

SUMMARY OF THE INVENTION

It is therefore the object of the present invention to specify a methodfor identifying an operating state during operation of a turbine andwith the aid of which systematic variations in the operating state canbe identified and displayed. It is also an object of the invention tospecify a device corresponding thereto.

The object directed to the method is achieved by the features of claims.Advantageous developments are specified in the subclaims.

The invention adopts a new path for identifying an operating stateduring operation of a turbine. To date, spatial temperature measurementsin which the exit temperature of the exhaust gas was detected have beenperformed in the exhaust gas duct at a number of positions. The spatialposition of each detected temperature has previously remainedunconsidered in this case. All the detected temperatures together withtheir respectively associated spatial position are now combined with oneanother with the formation of moments to form a resulting variable bymeans of which systematic variations can be identified more quickly andmore accurately.

The exhaust gas temperatures of an instant are plotted in a coordinatesystem while taking account of the location at which they are detected.Thereafter, each measured temperature value is projected onto the twoaxes of the coordinate system and is therefore respectively decomposedinto two spatial components perpendicular to one another in this caseand respectively directed either positively or negatively, theidentically directed spatial components subsequently being summed up foreach axis component by component with reference to a respectivereference value and with the formation of moments to form two momentsums, each reference value being selected such that the oppositelydirected moment sums are equally large, and that thereafter a pointcomposed from the two reference values is evaluated as centroid of theexit temperature distribution for the purpose of identifying theoperating state of the gas turbine.

Information that has previously been below the minimal conditions istaken into account by the use of the overall information of the exittemperature distribution. Moreover, this yields a higher level ofinformation content, which is used for the purpose of identifying statesmore quickly and more effectively.

In an advantageous refinement, the operating state is identified duringa stationary operation of the gas turbine as a disturbance when thecentroid can be represented as a vector having magnitude and angle, andwhen the current magnitude—orangle—of the centroid vector exhibits withreference to a magnitude—or angle—measured at an earlier

instant a difference that overshoots or undershoots a tolerance value.Two centroids detected at different instants are compared with oneanother, their difference being monitored. If the difference overshootsa tolerance value, a disturbance of the operation of the turbine isidentified. The tolerance values are determined by test operations or byempirical values.

From the opposite point of view, an undisturbed operation of the gasturbine can be diagnosed when the centroid vector remains constant inmagnitude and/or angle when viewed over time.

The temporal behavior of the magnitude and the angle of the centroidvector—the centroid of the exit temperature distribution—exhibits aknown response during operation of the turbine:

During undisturbed operation of the gas turbine, the centroid vector ofthe exit temperature distribution settles at a temporally constantmagnitude with a constant angle. Here, constant means that althoughslight changes can occur within the fluctuation range prescribed bytolerance values, they are nevertheless not to be ascribed to systematicinfluences, but to random ones.

If load changes occur, these have no influence on the magnitude of thecentroid vector, since the magnitude is fundamentally invariant withrespect to load changes.

The angle of the centroid vector is fundamentally dependent on loadchanges, since these are likewise accompanied by changes in the hot gasmass flow and thus in the flow conditions within the turbine. Thevariation in the hot gas mass flow results from the adjustments of thecompressor inlet guide vanes and/or from the variation in the fuel massflow that is fed.

The variations in the hot gas mass flow cause a corresponding rotationof the exit temperature distribution. However, this is not synonymouswith a disturbance, since this change in angle is to be ascribed toknown interventions in the operation of the gas turbine.

If there is a substantial change in the magnitude or the angle of thecentroid vector during stationary operation of the turbine, this is tobe ascribed to a systematic variation such as, for example, blocking ofthe ducts by a loosened thermal shielding brick. The systematicvariations are to be ascribed to defective operation or a disturbance ofthe gas turbine, since a known, external influence is lacking.Furthermore, combustion disturbances, which can be nozzle carbonization,on the one hand, or an altered flame alignment, on the other, lead tovariation in the centroid of the exit temperature distribution.Likewise, flow fluctuations that are reflected in temperaturefluctuations can lead to rotation of the angle.

A plane in which the measuring points for the temperature measuringdevices lie is expediently aligned perpendicular to the principal flowdirection of the exhaust gas, and the principal flow direction isparallel to the rotation axis of a shaft of the turbine. Thetemperatures are therefore tracked over time at an identical spacingfrom the rotation axis of the shaft.

In an advantageous development, the measuring points are arranged in afashion rotationally symmetrical relative to the rotation axis. Thisresults in an equidistant distribution that is particularly easy toevaluate because of the symmetry.

The method is suitable in general for continuously monitoring theoperation. It is very particularly advantageous in this case when themethod is preferably applied at every instant, that is to saycontinuously, during the stationary or quasi-stationary operation of theturbine, since the method delivers particularly reliable results here.The analysis of the state of the gas turbine operation with the aid ofthe centroid vector can, however, be carried out in principle evenduring a strongly transient operation—given suitable modifications—,there being a need to consider special features in transient operation.Reliable results and statements relating to the behavior of the gasturbine when traversing a transient operating state, for examplestarting operations and stopping operations, can consequently beinvestigated in detail.

The turbine is expediently designed as a gas turbine.

The object directed to the device is achieved by the features of claims.Advantageous developments are specified in the subclaims.

Each temperature measuring device is connected to an input of a singleevaluation device with the aid of which an operating state can becharacterized. The method described is then carried out in theevaluation device such that a signal for the operating state cantherefore be displayed at the output of the evaluation device.Consequently, the evaluation device has means for recording the detectedtemperature and means for identifying the operating state.

In an advantageous development, a plane in which the temperaturemeasuring devices are provided is transverse to the principal flowdirection of the exhaust gas, which runs parallel to the rotation axisof a shaft of the turbine. The temperature measuring devices lying inthe plane are provided at the inner wall of the exhaust gas housing suchthat all the spatial

measured temperature values are detected at the same spacing from therotation axis of the shaft. Identical conditions are therefore createdfor the temperature measuring devices; weighting of individual measuringpoints is not required.

The spatial measured temperature values can expediently be detected in afashion rotationally symmetrical relative to the rotation axis.

When the turbine has an annular combustion chamber at which a number ofburners are provided, and the number of burners is equal to the numberof temperature measuring devices, it is possible to relate burners tothe exhaust gas temperature measured in the exhaust gas duct.

If the turbine has a number of combustion chambers respectively havingone burner, it is possible to relate burners to the exhaust gastemperature measured in the exhaust gas duct even over a number oftemperature measuring devices when this number corresponds to the numberof combustion chambers.

The turbine is advantageously designed as a gas turbine.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is explained in more detail with the aid of a drawing, inwhich:

FIG. 1 shows a gas turbine in a longitudinal partial section,

FIG. 2 shows a Cartesian coordinate system with a diagram of the exittemperature distribution,

FIG. 3 shows a combined magnitude/time and angle/time diagram for acentroid vector of the exit temperature distribution of the gas turbine,and

FIG. 4 shows an evaluation device for the monitoring method.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a gas turbine 1 in a longitudinal partial section. It hasin the interior a rotor 3 that is mounted so as to rotate about arotation axis 2 and is also denoted as turbine rotor or rotor shaft.Following one after the other along the rotor 3 are an inlet housing 4,a compressor 5, a toroidal annular combustion chamber 6 with a number ofcoaxially arranged burners 7, a turbine 8 and an exhaust gas housing 9.

Provided in the compressor 5 is an annular compressor duct 10 thattapers in cross section in the direction of the annular combustionchamber 6. Arranged at the output, on the combustion chamber side, ofthe compressor 5 is a diffuser 11 that is connected to the annularcombustion chamber 6 in terms of flow. The annular combustion chamber 6forms a combustion space 12 for a mixture of a fuel and compressed airL. A hot gas duct 13 is connected to the combustion space 12 in terms offlow, the exhaust gas housing 9 being arranged downstream of the hot gasduct 13.

Vane rows are arranged in a respectively alternating fashion in thecompressor duct 10 and in the hot gas duct 13. A guide vane row 15formed from guide vanes 14 is respectively followed by a moving vane row17 formed from moving vanes 16. The stationary guide vanes 14 areconnected in this case to the stator 18, whereas the moving vanes 16 arefastened on the rotor 3 by means of a turbine disk 19.

The exhaust gas duct 9 is delimited by an inner wall 24 that isconcentric with the rotation axis 2 and on which twenty-four temperaturemeasuring devices M_(i) are arranged in a rotationally fixed fashion anddistributed uniformly over the circumference. All the temperaturemeasuring devices M_(i) lie here in an imaginary plane that isperpendicular to the rotation axis 2.

During operation of the gas turbine 1, air L is taken in through theintake housing 4 by the compressor 5, and compressed in the compressorduct 10. The air L provided at the output of the compressor 5 on theburner side is led to the burners 7 by the diffuser 11 and mixed therewith a fuel. The mixture is then burned in the combustion space 10 withthe formation of a working fluid 20. From there, the working fluid 20flows into the hot gas duct 13. The working fluid 20 expands at theguide vanes 16 arranged in the turbine 8 and at the moving vanes 18 inan impulse-transmitting manner such that the rotor 3 is driven and, withit, so is a driven machine (not illustrated) connected to it. Theworking fluid 20 is passed on as exhaust gas in the exhaust gas duct 9.Each temperature measuring device M_(i) then measures the temperatureT_(i) of the exhaust gas prevailing at its location.

FIG. 2 shows a Cartesian coordinate system P(x,y) with an exittemperature distribution at an instant t₀.

The following definitions are made:

-   P(x,y)=a Cartesian coordinate system lying in the plane and which is    intersected at right angles by the rotation axis 2 at the origin of    coordinates P(0,0),-   M_(i)=the temperature measuring devices whose measuring points lie    in the plane,-   n=24, the number of temperature measuring devices,-   T_(i)=temperature of the temperature measuring device M_(i), for i=1    . . . n

Extending in the form of rays from the origin of coordinates P(0,0) inthe coordinate system P(x,y) are twenty-four auxiliary straight linesH_(i), for i=1 . . . n, in relation to each measuring point of thetemperature measuring devices M_(i). Each auxiliary straight line H_(i)therefore exhibits with reference to the positive x-axis an angle Θ_(i)whose value is 15° or an integral multiple thereof.

For each temperature T_(i) detected by the temperature measuring devicesM_(i) there is plotted on its associated auxiliary axis H_(i) a pointwhose distance from the origin of coordinates P(0,0) is proportional tothe detected magnitude of the temperature T_(i). This results on eachauxiliary axis H_(i), i=1 . . . n in a point dependent on the localtemperature T_(i). The known trigonometrical functions are then used foreach point in accordance withT _(x) _(i) =T _(i)·cos(Θ_(i)), for i=1 . . . 24  (1)T _(y) _(i) =T _(i)·sin(Θ_(i)), for i=1 . . . 24  (2)to make a projection onto the two axes of the coordinate system.

In order to achieve an identical weighting of the measuring points, thetemperature measuring devices M_(i) are all arranged lying in a planethat extends perpendicular to the rotation axis 2 and therefore, at thesame time, to the principal flow direction of the exhaust gas. Anothernonuniform distribution of the temperature measuring devices M_(i) overthe circumference could likewise be carried out with the aid of themethod.

In order to be able to determine a centroid S of the exit temperaturedistribution of the exhaust gas, the moments of the individualtemperatures T_(i) about the centroid S need to be in equilibrium.During the component by component consideration, that is to say for eachaxis of the coordinate system in each direction, it is thereforenecessary in each case for the sums of the oppositely directed momentsin accordance with $\begin{matrix}{{{{\sum\limits_{i = 1}^{6}M_{+ {xi}}} + {\sum\limits_{i = 19}^{24}M_{+ {xi}}}} = {\sum\limits_{i = 7}^{18}M_{- {xi}}}}{and}} & (3) \\{{\sum\limits_{i = 1}^{12}M_{+ y_{i}}} = {\sum\limits_{i = 13}^{24}M_{- y_{i}}}} & (4)\end{matrix}$to be in equilibrium. Each individual moment is calculated from a leverarm pivoted at the centroid S and which is multiplied by the componentacting at the other end of the lever arm, that is to say the effectiveportion of the temperature T_(i). Since the centroid is unknown atfirst, the moments are calculated in the coordinate system component bycomponent with reference to an as yet unknown reference value T_(GL), inaccordance withM _(+x) _(i) =(T _(+x) _(i) −T _(xGL))·T _(+x) _(i)   (5)M _(−x) _(i) =(T _(−x) _(i) +T _(xGL))·T _(x) _(i)   (6)M _(+y) _(i) =(T _(+y) _(i) −T _(yGL))·T _(+y) _(i)   (7)M _(−y) _(i) =(T _(−y) _(i) +T _(yGL))·T _(−y) _(i)   (8).

In order to calculate the centroid S, equations (5) and (6) aresubstituted in equation (3), and equations (7) and (8) are substitutedin equation (4), and transformation is performed such that the referencevalue of the x-axis can be determined in accordance with $\begin{matrix}{T_{xGL} = \frac{{\sum\limits_{i = 1}^{6}T_{+ x_{i}}^{2}} + {\sum\limits_{i = 19}^{24}T_{+ x_{i}}^{2}} - {\sum\limits_{i = 7}^{18}T_{- x_{i}}^{2}}}{{\sum\limits_{i = 1}^{6}T_{+ x_{i}}} + {\sum\limits_{i = 7}^{18}T_{- x_{i}}} + {\sum\limits_{i = 19}^{24}T_{+ x_{i}}}}} & (9)\end{matrix}$and that of the y-axis can be determined in accordance with$\begin{matrix}{T_{yGL} = {\frac{{\sum\limits_{i = 1}^{12}T_{+ y_{i}}^{2}} - {\sum\limits_{i = 13}^{24}T_{- y_{i}}^{2}}}{{\sum\limits_{i = 1}^{12}T_{+ y_{i}}} + {\sum\limits_{i = 13}^{24}T_{- y_{i}}}}.}} & (10)\end{matrix}$

The two reference values can then be combined as one centroid vector{overscore (S)}_(ges) in accordance with magnitude|{overscore (S)} _(ges)=√{square root over (T _(xGL) ² +T _(yGL)²)}  (11)and angle $\begin{matrix}{\varphi_{ges} = {\tan\left( \frac{T_{yGL}}{T_{xGL}} \right)}} & (12)\end{matrix}$

The origin of the centroid vector {overscore (S)}_(ges) is situated hereat the origin of coordinates P(0,0) and ends at the centroid S that liesat the point P(T_(,xGL), T_(yGL)). The angle φ_(ges) is referred to thepositive x-axis in the mathematically positive sense, it being necessarywhen applying the tangent function to apply the customary considerationsfor the magnitude of the angle φ_(ges).

All the determined temperatures T_(i) are combined in accordance withthe above calculation to form a centroid vector {overscore (S)}_(ges) ina a time-resolved—that is to say constantly recurring—fashion.

In FIG. 2, the points of the temperatures T_(i) plotted on the auxiliaryaxes H_(i) are interconnected via a circumferential line 22 such thatthey jointly enclose a polygonal, virtually circular surface 23 whosecentroid S is determined by applying the method.

The null vector would necessarily be yielded as centroid vector{overscore (S)}_(ges) for an ideal gas turbine 1 with a symmetrical exittemperature distribution.

If the magnitude |{overscore (S)}_(ges)| of the centroid vector{overscore (S)}_(ges) increases substantially, the exit temperaturedistribution referring to the origin of the coordinate system is thenincreasingly deformed. If the magnitude |{overscore (S)}_(ges)|decreases, the exit temperature distribution becomes more symmetrical.

FIG. 3 illustrates the time profile of the centroid vector {overscore(S)}_(ges) in a combined magnitude/time and angle/time diagram. Thecentroid vector {overscore (S)}_(ges) is described by the magnitude|{overscore (S)}_(ges)| and the angle φ_(ges), the angle φ_(ges) beingillustrated with a dashed type of line, and the magnitude |{overscore(S)}_(ges)| being illustrated as a continuous line.

In the stationary undisturbed operation of the gas turbine starting fromthe instant t=t₀ up to the instant t=t₁, the characteristic of themagnitude |{overscore (S)}_(ges)| runs in an approximately constantfashion inside a narrow fluctuation range. The angle φ_(ges) is likewiseto be considered as constant inside a narrow fluctuation range.

At the instant t=t₁, a systematic variation that is identified by meansof the method occurs during the stationary operation by means of apartial blockade of the turbine entrance space.

Starting from the instant t=t₁, the angle φ_(ges) changes substantiallyand drops approximately to half of its previous value. Starting from theinstant t=t₂, the magnitude |{overscore (S)}_(ges)| moves outside itsfluctuation range. The disturbance can be identified earlier and moreeasily owing to the not insubstantial change in the angle φ_(ges) and inthe magnitude |{overscore (S)}_(ges)|.

Although the temperature changes were recorded with the aid of themonitoring methods previously known from the prior art, the slightsystematic temperature changes do not overshoot the limiting values, andso no defective operation was diagnosed. Consequently, this case ofdisturbance—the partial blockade of the turbine entrance space with,resulting therefrom, excitations of vibrations of the first moving vanerow, and subsequent vane breakages—was not identified early enough withthe aid of a monitoring method in accordance with EP 1 118 920 A1.

The method described in EP 1 118 920 A1 does decompose the determinedsliding mean values into two mutually perpendicular components fromwhich a resulting variable having magnitude and angle is determined, butno weighting of the components is performed there, in particular novariable weighting, in the manner of a formation of moments. In theinventive method, each temperature T_(i), for example the temperatureT_(+xi), acts with the lever arm assigned to it, for example T_(+xi)minus T_(xGL),—in a way comparable to a formation of moments in thephysical sense—about the centroid S of the surface that is to bedetermined; in accordance with equations (5) to (8).

The displacement of the centroid S, that is to say the pointP(T_(xGL),T_(yGL)), also changes each lever arm and thus the weightingof each temperature T_(i). Consequently, the inventive method becomesextremely sensitive with respect to the smallest changes in the exittemperature distribution. In addition, the method constitutes a furtherimprovement by comparison with the simple formation of mean values,since this simple formation of mean values, does not necessarily exhibitsymmetrical temperature displacements, and provides no informationrelating to the geometrical alignment and rotation of the exittemperature distribution.

FIG. 4 shows the device for monitoring the centroid vector {overscore(S)}_(ges). It has an evaluation device 25 that applies the method. Inthis case, the evaluation device 25 is connected to all the temperaturemeasuring devices M_(i) and to a display device 26. The evaluationdevice 25 uses the detected temperatures T_(i) to calculate the centroidvector {overscore (S)}_(ges), and checks whether the magnitude|{overscore (S)}_(ges)| thereof or the angle φ_(ges) thereof liesoutside a tolerance interval. If this is the case, the evaluation device25 generates a signal for the display device 26 that then displays adisturbance as operating state. The display device 26 can be a monitoror a pilot lamp.

By continuously monitoring the magnitude |{overscore (S)}_(ges) and theangle φ_(ges), it is possible to identify the temporal change thereof atan early stage as a systematic variation in the absence of an externalknown influence. These then indicate defects or disturbances at an earlystage such that consequential damage to the gas turbine can be avoided,or such that a well-timed intervention can be made in the operation ofthe turbine for corrective purposes.

1-12. (canceled)
 13. A method for identifying an operating state duringan operation of a turbine having an exhaust gas flowing through anexhaust gas housing downstream of the turbine, comprising: detectingtemperature values of the exhaust gas in the exhaust gas housing in atime-resolved fashion and in a plane transverse to principal flowdirection of the exhaust gas; measuring the temperature values of theexhaust gas in a spatially resolved fashion with reference to an originof an imaginary Cartesian coordinate system; projecting the measuredtemperature values into two axes of the imaginary Cartesian coordinatesystem; decomposing the measured temperature values into two spatialcomponents perpendicular to one another; directing the two spatialcomponents either positively or negatively at the imaginary Cartesiancoordinate system; calculating a moment from a lever arm that is pivotedat two reference values of the two axes of the imaginary Cartesiancoordinate system; summing up moments for the two axes to form twooppositely directed moment sums; evaluating the two reference valuesfrom the two moment sums; and composing a point from the two referencevalues as a centroid of the temperature distribution.
 14. The method asclaimed in claim 13, wherein the two respective reference values areselected such that the two oppositely directed moment sums are equal.15. The method as claimed in claim 13, wherein the lever arm is amultiple of an effective portion of the measured temperature values atone of the two axes with respective one of the two spatial components ofthe measured temperature values.
 16. The method as claimed in claim 13,wherein the centroid is a vector having magnitude and angle, and theoperating state is identified as a disturbance when the differencebetween magnitude or angle of a current centroid vector with referenceto magnitude or angle of an earlier measured centroid vector exceeds atolerance value.
 17. The method as claimed in claim 13, wherein theplane is perpendicular to the principal flow direction of the exhaustgas, and the principal flow direction is parallel to a rotation axis ofa shaft of the turbine.
 18. The method as claimed in claim 13, whereinthe measured temperature values are detected at a same spacing from therotation axis of the shaft of the turbine.
 19. The method as claimed inclaim 13, wherein the measured temperature values are detected in afashion rotationally symmetrical relative to the rotation axis of theshaft of the turbine.
 20. The method as claimed in claim 13, wherein theoperation of the turbine is a stationary operation of the turbine.
 21. Adevice for identifying an operating state during an operation of aturbine having an exhaust gas flowing through an exhaust gas housingdownstream of the turbine, comprising: a plurality of temperaturemeasuring devices which are arranged along an inner wall of the exhaustgas housing of the turbine and in a plane transverse to principle flowdirection of the exhaust gas, the temperature measuring devicesproviding a plurality of measured temperature values in a time-resolvedfashion and in a spatially resolved fashion with reference to an originof an imaginary Cartesian coordinate system; a projector that projectsthe measured temperature values into two axes of the imaginary Cartesiancoordinate system and decomposes the measured temperature values intotwo spatial components perpendicular to one another that are directedeither positively or negatively at the imaginary Cartesian coordinatesystem; a calculator that calculates a moment from a lever arm that ispivoted at two reference values of the two axes of the imaginaryCartesian coordinate system and sum up moments for the two axes to formtwo oppositely directed moment sums; and an evaluation device thatevaluates the two respectively reference values from the two moment sumsand compose a point from the two reference values as a centroid of thetemperature distribution.
 22. The device as claimed in claim 21, whereinthe measured temperature values are inputs of the evaluation device. 23.The device as claimed in claim 21, wherein a signal of the operatingstate is displayed as an output of the evaluation device.
 24. The deviceas claimed in claim 21, wherein the evaluation device is connected tothe temperature measuring devices.
 25. The device as claimed in claim21, wherein the plane is perpendicular to the principal flow directionof the exhaust gas, and the principal flow direction is parallel to arotation axis of a shaft of the turbine.
 26. The device as claimed inclaim 21, wherein the measured temperature values are detected at a samespacing from the rotation axis of the shaft of the turbine.
 27. Thedevice as claimed in claim 21, wherein the measured temperature valuesare detected in a fashion rotationally symmetrical relative to therotation axis of the shaft of the turbine.
 28. The device as claimed inclaim 21, wherein the turbine has an annular combustion chamber with aplurality of burners and the number of the burners is equal to thenumber of measuring devices.
 29. The device as claimed in claim 21,wherein the turbine has a plurality of combustion chambers with oneburner and the number of the combustion chambers is equal to the numberof measuring devices.
 30. The device as claimed in claim 21, wherein theturbine is a gas turbine.